Truing caliper



OCL 23, 1934. J H, BRYANS 1,977,754

TRUING CALIPER Filed July 15, 1932 Patented 23 1934 l i:

- re! -STATE s PATENT Fries TRUING CALIBER; v l James l lerbert Bryans I, N

Application mly"15,1932 Serial naczawr -2" o1aims.f(o1f. 334209311 i This invention relates to acaliper designed pri-' the'finger 8. are slotted lgor ig tudinallyof'the tool, rnarily for-.use in truing the balance wheels of as'indicjated atll and l'z res'pe'ctively; and exwatches. While calipers for the purpose have tendin'g'throu gh thesefslots isj an indicator bar already been devised it, has not been possible 13; one endofwhichisjsldtted;longitudinallyas '5 with any of them to obtain an unobstructed view at 14 and pivotally and slidably "conneotedby a so of the hairspring collet. Nor has it been possible screw 15 to a supporting bar 16 mounted on the to true the hairspring while on the balance wheel. pivot 3. Bar 13 carries an angularly adjustable It is an object of the present invention to indicator 1'? which is reversible on a pivot 18 provide a very simple, compact and eflicient truand has oppositely extending points 19 for ening and poising tool which fits comfortably in gagement and actuation by the thumb and fore- 65 the hand and can be both adjusted and locked finger holding the tool. A binding screw, 20 is by the fingers of the hand holding it. extended through the extension 10 and has a A further object of the invention is to provide small lever or finger piece 21 by means of which a tool which allows the user to operate on the it can be quickly rotated. A slide 22 is carried innermost 6011 Of the hairspling with truing by finger 8 and projects into the slot 12. Thus 70 tweezers, this being possible because of the conwhen the screw is tightened this slide 22 venient access afforded as a result of the peculiar will be gripped and finger 8 will be held tightly construction and arrangement of the bearing against movement relative to extension 10. portions. In practice the screw 20 is rotated to release 20 With the foregoing and other objects in View finger 8 and the construction of the tool is such 75 which will appear as the description proceeds, that when the bearings 6 and 7 are adjusted to the invention resides in the combination and arthe pins of balance Wheels of any sizes, the wheel rangement of parts and in the details of conwill be held substantially parallel with the censtruction hereinafter described and claimed, it tral longitudinal axis of the tool.

25 being understood that changes in the precise em- After the pin P of the balance wheel W has 80 bodiment of the invention herein disclosed may been placed in position the arms 1 and 2 are be made within the scope of what is claimed pressed toward each other so that the bearwithout departing from the spirit of the inven ings 7 and 6 will engage the end of the pin.

- tion. The arms are then looked against relative move- In t e a c p y ing the preferred ment by pulling on lever 21. Screw 4 is adjusted 85 form of the invention has been shown. to relieve the pin from excessive pressure and In said drawing: to permit the balance wheel to rotate freely. In-

Fi ur 1 is an nl r d id l v tion of h dicator 17 is then adjusted to the rim of the a p Showing a balance Wheel in p s balance wheel and the caliper can be used as thereon. V ordinarily. The indicator 1'7 has two gauging fin- 90 Figure 2 is a Section on line Figure 1. gers and it can be reversed on its pivot 18 so Figure 3 is a Section 011 line igure 1. as to bring the active head of either finger into Figure 4 i5 Section 011 line Figure operative position relative to the wheel being Referring to the fi u s by C a acte of trued. By referring particularly to Figure 2 it 40 r n 1 nd 2 i na h p n bottom will be noted that the two fingers are of difierent 9 arms of the Caliper, these being p ota y sizes and proportions so that one of them can nected at one end, as shown at 3. The other end b ed to advantage in truing a wheel of one of the arm 2 h a r w 4 x n in h r size while the other can be used to advantage in 7 through provided at its lower end With a head truing a wheel of a smaller size. When one of 5 by means of which it n be rotated r ily. the gauging fingers is adjusted to position close 10 The other end 6 of the screw provides one of the t t periphery of th h 1 d t wheel bea for the pin of the balance wheel. tated, it can be determined, by close observation Arm 1 has its free e d d d a d Offset of the wheel, whether its periphery moves toward form an p bearing 7 for the other end the gauging finger as it rotates between its bearof the pin, this bearing 7 being tapered as indiings, 0

cated clearly in Figure 2. Importance is attached to the fact that the 'Extending from arm 1 is an arcuate guide finend of the pin nearest the hairspring is seated ger 8 concentric with the pivot 3 and slidable in the offset bearing 7. Thus the user has an within an arcuate slot 9 formed in an extension unobstructed view of the collet of the hair- 10 carried by the arm 2. Both the extension and spring and can work on the innermost convolution of the spring with tweezers. The tool therefore, constitutes a combined truing and poising tool which enables the workman to true the hairspring while on the balance wheel. It will be noted that all operations can be performed with the thumb and forefinger of the hand holding the caliper and the shape of the tool is such that it can be held comfortably in the hand.

The other hand of the user is leftfree to work on the balance'wheel and spring-.1 What is claimed is:

1. A caliper including opposed arms-pivotally connected at one end, fixed and adjustable bearings on the other ends of the respective arms,

the fixed bearing being extended outwardly'from.

its arm to expose the collet and the inner convolution of the hairspring of a supported balance wheel, an arcuate guide finger extending {romone of the arms, a slotted extension on the other arm slidably engaged by said fingerya supportthe bar and for cooperation with the rim of a supported balance wheel, said indicator having a projecting point for engagement by a finger of the. hand holding the caliper.

2. A caliper for supporting the pin of a balance wheel with its hairspring collet and the innermost convolution of the hairspring exposed to view and for engagement by tweezers or the like, said caliper comprisingopposed arms pivotallyconnected at one 'end, a bearing extending away from "one of the arms at its other end and offset toward the other arm, said bearing being reduced for engagement by that end of the pin nearest the hairspring, an adjustable bearing for the other end of the pin mounted in the corresponding end of the other arm, pivotally and slidably connected bars having all portions thereof supported between the planes defined by the side surfaces of the arms and extending from and supported by the pivotal connection of the arms, and an indicator mounted for rotation on one of "the barsabout an axis intersecting the arms for cooperation withthe rim of a supported balance wheel. "JAMES HERBERT BRYANS. 

